Dyeing artificial silk



now upon the market, rendered viscousby Patented Jan. 31, 1928.

UNITED STATES PATENT OFFICE.

CHARLES SAMUEL BEDFORD, 0F LEEDS, ENGLAND.

This invention artificial silk and proved methodof dyeing s the various fibres consisting of cellulose the acetyl, xanthate or extruded through spin- By artificial similar process silk I mean and nerets of suitable diameter to filaments Up to ticable to dye this mate of logwood owing oxide, the use the fibre.

According perty matter a good black celanese requir the silk so treate sodium bichromate,

of any de the present it h mg with logwoo to the of logwo but acetyl chromium to be steeped d is placed in a hotbath of DYEING ARTIFICIAL SILK.

No Drawing. Application filed August 31, 1926, Serial No. 132,899, and' in Great Britain September relates to the dyeing of has for its object an imuch silk.

form silk-like sired grade or denier.

as not been pracrial blaek'by means fact that chromium which is inherent to dyed, exhibits little afiinity for to this invention I have found have the remarkable prood colouring ution which can thereby becombrown in colour.

used cold or fibres develop to with logwood silk such as hot. When oxide is fixed and an intense black is obtained.

After in soap, and milling.

washing hot and a li the shadesare fast to oiling, soap describe ht scouring amples, which are by no a particular out my invention in the case of cellulose acetate (celanese) silk.

E wample 1.Ce

silk, yarn or fabric is steeped The silk is tr taken out and through rollers,

passed into a solution of sodium bi ture not less than to develop at pleted in 10 to 30 be passed into a cold chrome ally heated up The chrome any other add visable especia eate llulose acetate celanese ina bath consisting of a solution of from 2 to 5% logwood crystals or hematine.

d in this manner at a tem- C. preferably at It is then. or pressed bath containing a 1 to 3% once an to C.

bath ,may' be ition whatever,

lly when acid chromate at a tempera- C. The black begins d the dyeing is comminutes, or the silk may bath and gradu-' used without but it is adhas been used the celanese silk remains undyed.

with the logwood dye to add a little chalk or mild alkali, such as sodium carbonate or bi-carbonate, sodium acetate, ammonium carbonate, or borax; this causes the black formed to be a bluer shade.

Both the logwood and the chrome baths can be used for dyeing successivelots of silk, but they require strengthening by further additions'of hematine and sodium bichromate. Finally by addition of about 5% of common salt or of Glaubers salt without further addition of water they may be economically exhausted.

In other cases I steep silk in a 2 to 5% solution of logwood crystals or hematine, alone or with addition of 5% (on the water) Turkey red oil. After steeping for 10 to 30 minutes the fibre .is taken out, rolled or whizzed, and dried. The black is developed in a hot solution of sodium bichromate as above described.

It is obvious that the process is equally suited for dyeing-piece goods as 'well as yarn, also for goods consisting in part of -wool or natural silk. Example E2.-Viscose silk is treated exactly as described in Example 1, but the temperature of the logwood bath may range from 20 to 93 C. The temperature of the chrome in the case of viscose may be varied from 20 to 93 C. I am of o inion however that faster shades are given by using a hot chrome bath.

Example 3.-Wl 1en treating a fabric consisting of a mixture of cellulose acetate (celanese) and viscose artificial silk, if, for an reason, it is desirable to leave the cellu ose acetatecelanese silk undyed, the fabric after treatment with logwood dye in the cold is developed in cold sodium bichromate solution (from 1 to 3%). By this means black is developed on the The oelanese silk can afterwards be dyed up with suitable colours to produce mixed colour effects.

viscose silk but What I claim and desire Letters Patent is 1. The process of dyeing yarns and fabrics comprising artificial silk, consisting in first impregnating the fibre with logwood dye, and subsequently developing in a solution of alkali bichromate.

2. The process of dyeing yarns and fabrics comprising artificial silk, consisting in first impregnating the fibre with logwood dye, and subsequently sodium bichromate.

3. The process of dyeing yarns and fabrics constituted by a mixture of cellulose acetate and viscose silks, consisting in impregnating the fibres with logwood dye and afterwards developing in alkali bichromate solution.

4. The process of dyeing yarns and fabrics constituted by a mixture of cellulose acetate and viscose silks, consisting in impregnating the fibres with logwood dye and afterwards develo ing in sodium bichromate solution.

5. T 1e process of dyeing yarns and'fabrics comprising artificial silk, consisting in first impregnating the fibre with logwood dye, and subsequently developing a black by steeping in a solution of alkali bichromate at a temperature of from to 100 C.

6. The process of dyeing yarns and fabrics comprising artificial silk, consisting in first im regnating the fibre with logwood dye, an subsequentl developing a black by steeping in a so ution of alkali bichromate at a temperature of from 60 to 100 C. to

to secure by which has been added a mild alkali.

7. The process of dyeing yarns and fabrics comprising artificial silk, consisting in first impregnating the fibre with logwood dye,

developing in a solution of and subsequently developing a black by steeping in a solution of alkali bichromate at a temperature of from 60 to 100 C. to which has been added borax.

8. The process of dyeing yarns and fabrics comprising artificial silk, consisting in first impregnating the fibre with logwood dye and subsequently developing a black by steeping in a solution of sodium bichromatc at a temperature of from (30 to 100" C.

9. The process of dyeing yarns and fabrics comprising artificial silk, consisting in first impregnating the fibre with logwood dye to which Turkey red oil has been added, and subsequently developing a black by steeping in a solution of sodium bichromate at a temperature of from 60" to 100 C. i

10. Yarns and fabrics comprising artificial silk dyed by impregnatin with logwood dye and subsequently deve loping in a solution of alkali bichromate.

11. Yarns and fabrics comprising artificial silk constituted by a mixture of cellulose acetate and viscose silks, dyed by impregnating the fibres with logwood dye and afterwards developing in alkali bichromate solution.

12. The process of dyeing yarns and fabrics comprising artificial silk, consisting in first impregnating the fibre with logwood dye, and subsequently developing a black by steeping in a solution of alkali bichromate at a temperature of from 60 to 100 C. to which has been added sodium acetate.

In testimony whereof I aflix my signature.

CHARLES SAMUEL BEDFORD. 

